Storage tanks or holding bins are typically utilized to store corn or other types of grain. Such bins are usually about twenty feet high and can store between about 1,000 and 50,000 bushels or more of grain.
Keeping track of the amount of grain in such bins, however, has been a long-standing problem, to which there have been various approaches. One approach has been to track the number of truck loads of grain put in versus the number of truck loads removed from the bin. This of course requires use of trucks of the same size for loading and unloading, or if not, some computation to take into account different truck sizes. Another approach has been simply to climb a ladder on the side of the bin and knock on the wall, or look into the opening on the top of bin and count the number of exposed marking rings inside the bin. However, climbing ladders is tiring and time consuming, and can be dangerous--particularly at night and/or under adverse conditions when the ladder rungs are slippery from rain, dew, frost, sleet and the like. Yet another approach has been to put windows in the walls of the bins, however, these can quickly become dirty and the grain color therein usually does not provide enough contrast for easy viewing.
It will be appreciated that these prior approaches provide only rough approximations of material in the bin. A more accurate measurement of the grain in the holding bin is desirable, especially when using a grain dryer, which must be full to operate efficiently on a batch basis.
Level indicators for granulate storage tanks have been devised heretofore. For example, U.S. Pat. Nos. 3,290,938, 3,401,562 and 4,043,199 are representative of the prior art in this regard. These devices, however, have tended to be complicated and thus expensive.
A need has thus arisen for an improved visual indicator or gauge of simplified construction which will provide a positive, remote on/off visual indication of some condition, such as the level of grain in the bin without climbing any ladders.